Green Starch-Based Hydrogels with Excellent Injectability, Self-Healing, Adhesion, Photothermal Effect, and Antibacterial Activity for Promoting Wound Healing.

Hydrogel materials have proven valuable in wound healing, but improving the safety of these hydrogels is still challenging. Therefore, designing multifunctional natural polymeric-based hydrogels with excellent mechanical properties to replace toxic or potentially risky, refractory chemical polymer-based hydrogels such as polyacrylamide and polyethylene glycol is of particular significance. Here, a green starch-based hydrogel (Starch@Ca/CGC hydrogel) with injectability, self-healing, and instant adhesion was constructed by coordination interaction, electrostatic interaction, and intramolecular and intermolecular hydrogen bonds. Therein, natural bioactive small molecules gallic acid (GA) and carvacrol (CA) were coordinated with metal ions by the ultrasonic-triggered self-assembly and ionic cross-linking codriven strategy to prepare Cu-gallic acid-carvacrol nanospheres (CGC NPs), which conferred the hydrogel with near-infrared light (NIR)-controlled CA release and photothermal synergistic sterilization properties, as well as antioxidant and anti-infection capabilities. More importantly, the multifunctional hydrogel platforms could completely cover an irregular wound shape to prevent secondary injury and significantly accelerate wound healing under NIR with more skin appendages like hair follicles and blood vessels appearing. Therefore, it is expected that this starch-based hydrogel could serve as a competitive multifunctional dressing in the biomedical field, including bacteria-derived wound infection and other tissue repair.

Effect of traditional Chinese medicine external therapy for functional constipation: a meta-analysis.

OBJECTIVE: To systematically review the effectiveness and safety of external treatment with traditional Chinese medicine in patients with functional constipation. METHODS: In this meta-analysis study, we searched for randomized controlled trials (RCTs) on traditional Chinese medicine (TCM) external therapy for treating functional constipation from various databases. Search time was from database establishment to May 2022. The included studies were evaluated for meta-analysis using RevMan 5.3 software. RESULTS: A total of 18 randomized controlled studies were included, including 1404 patients. Results showed the total effective rate [OR = 3.83, 95% CI (2.71, 5.43), P < 0.01] and quality of life [OR = -9.78, 95% CI (-12.32, -7.23), P < 0.01] effectively improved after TCM external therapy; constipation symptoms [OR = -1.64, 95% CI (-2.31, -0.96), P < 0.01] reduced; defecation time [OR = -0.68, 95% CI (-0.99, -0.37), P < 0.01] shortened and spontaneous complete bowel movements (SCBM) [OR = 0.48, 95% CI (0.01, 0.95), P < 0.05] increased; and recurrence rate [OR = 0.25, 95% CI (0.17, 0.38), P < 0.01] reduced. The results of a subgroup analysis of the types of TCM treatment showed acupoint catgut embedding [OR = 3.04, 95% CI (1.10, 8.41), P < 0.05], acupoint application [OR = 3.46, 95% CI (1.74, 6.89), P < 0.01], manipulation [OR = 4.26, 95% CI (0.81, 22.53), P > 0.05], the combination of two external treatment methods [OR = 7.73, 95% CI (3.00, 19.91), P < 0.01], acupuncture [OR = 3.09, 95% CI (1.21, 7.85), P < 0.05], and other external therapies [OR = 3.58, 95% CI (1.89, 6.80), P < 0.01] had certain value in treating functional constipation. CONCLUSIONS: TCM external therapy has good clinical efficacy in treating functional constipation (FC) patients, which can improve main treatment efficacy and life quality, reduce constipation symptoms, shorten defecation time and SCBM, and reduce the recurrence rate. This therapy has no adverse reaction and can be widely applied in clinical practice.

Recent Advances on Development of Hydroxyapatite Coating on Biodegradable Magnesium Alloys: A Review.

The wide application of magnesium alloys as biodegradable implant materials is limited because of their fast degradation rate. Hydroxyapatite (HA) coating can reduce the degradation rate of Mg alloys and improve the biological activity of Mg alloys, and has the ability of bone induction and bone conduction. The preparation of HA coating on the surface of degradable Mg alloys can improve the existing problems, to a certain extent. This paper reviewed different preparation methods of HA coatings on biodegradable Mg alloys, and their effects on magnesium alloys' degradation, biocompatibility, and osteogenic properties. However, no coating prepared can meet the above requirements. There was a lack of systematic research on the degradation of coating samples in vivo, and the osteogenic performance. Therefore, future research can focus on combining existing coating preparation technology and complementary advantages to develop new coating preparation techniques, to obtain more balanced coatings. Second, further study on the metabolic mechanism of HA-coated Mg alloys in vivo can help to predict its degradation behavior, and finally achieve controllable degradation, and further promote the study of the osteogenic effect of HA-coated Mg alloys in vivo.

Ca2+, pH and thermo triple-responsive mechanized Zr-based MOFs for on-command drug release in bone diseases.

We report a new approach towards the design of multi-stimuli responsive "gated scaffolds" based on the combination of capped metal-organic frameworks (MOFs) and supramolecular[2]pseudorotaxanes. These mechanized Zr-MOFs showed negligible premature release, high drug encapsulation, low cytotoxicity and good biocompatibility. Around or inside the bone tumour cells, the pH, lysosomal pH, and osteoclast pH are observed to be lowered (acidosis), and thus the resulting osteolysis increases the Ca2+ concentration (hypercalcemia). The drug release from the mechanized MOFs was triggered by the simultaneous variations of pH and Ca2+ concentration in bone tumour cells. Hyperthermia (also called thermal therapy or thermotherapy) as a popular type of cancer treatment technique can also control drug release in the above-mentioned system. This design opens up the possibility of developing smart biomaterials for bone regeneration and cancer therapy.

Effect of hydrion evolution by polylactic-co-glycolic acid coating on degradation rate of pure iron.

For biodegradable iron coronary stents, the major problem is the low degradation rate in body environment. In this study, a new strategy was proposed to increase the degradation rate of iron in vitro. The hydrion evolution was intended to be introduced into the degradation system to increase the degradation rate. To realize this strategy, polylactic-co-glycolic acid (PLGA) was coated onto the surface of pure iron. The degradation process and mechanism of pure iron coated with PLGA were investigated. The results showed that iron coated with PLGA exhibited higher degradation rate in the static immersion test all along. With the degradation of PLGA, the oligomers of PLGA could release abundant H(+) which could dissolve the ferrous oxide to make the electrolyte and oxygen to reach the surface of iron again and simultaneity trigger the hydrion evolution at the middle stage of the degradation. The study also revealed that the solution ions failed to permeate the PLGA coating and the deposition of calcium and phosphorus in the degradation layer was inhibited which further enhanced the degradation.

[Biocompatibility of silicon containing micro-arc oxidation coated magnesium alloy ZK60 with osteoblasts cultured in vitro].

OBJECTIVE: To research in vitro biocompatibility of silicon containing micro-arc oxidation (MAO) coated magnesium alloy ZK60 with osteoblasts. METHODS: The surface microstructure of silicon containing MAO coated magnesium alloy ZK60 was observed by a scanning electron microscopy (SEM), and chemical composition of the coating surface was determined by energy dispersive spectrum analysis. The experiments were divided into 4 groups: silicon containing MAO coated magnesium alloy ZK60 group (group A), uncoated magnesium alloy ZK60 group (group B), titanium alloy group (group C), and negative control group (group D). Extracts were prepared respectively with the surface area to extraction medium ratio (1.25 cm(2)/mL) according to ISO 10993-12 standard in groups A, B, and C, and were used to culture osteoblasts MC3T3-E1. The a-MEM medium supplemented with 10% fetal bovine serum was used as negative control in group D. The cell morphology was observed by inverted phase contrast microscopy. MTT assay was used to determine the cell viability. The activity of alkaline phosphatase (ALP) was detected. Cell attachment morphology on the surface of different samples was observed by SEM. The capability of protein adsorption of the coating surface was assayed, then DAPI and calcein-AM/ethidium homodimer 1 (calcein-AM/EthD-1) staining were carried out to observe cell adhesion and growth status. RESULTS: The surface characterization showed a rough and porous layer with major composition of Mg, O, and Si on the surface of silicon containing MAO coated magnesium alloy ZK60 by SEM. After cultured with the extract, cells grew well and presented good shape in all groups by inverted phase contrast microscopy, group A was even better than the other groups. At 5 days, MTT assay showed that group A presented a higher cell proliferation than the other groups (P < 0.05). Osteoblasts in groups A and C presented a better cell extension than group B under SEM, and group A exhibited better cell adhesion and affinity. Protein adsorption in group A [ (152.7 +/- 6.3) microg/mL] was significantly higher than that of group B [(96.3 +/-3.9) microg/mL] and group C [ (96.1 +/-8.7) microg/mL] (P < 0.05). At each time point, the adherent cells on the sample surface of group A were significantly more than those of groups B and C (P < 0.05). The calcein-AM/EthD-1 staining showed that groups A and C presented better cell adhesion and growth status than group B. The ALP activities in groups A and B were 15.55 +/-0.29 and 13.75 +/-0.44 respectively, which were significantly higher than those in group C (10.43 +/-0.79) and group D (10.73 +/-0.47) (P < 0.05), and group A was significantly higher than group B (P < 0.05). CONCLUSION: The silicon containing MAO coated magnesium alloy ZK60 has obvious promoting effects on the proliferation, adhesion, and differentiation of osteoblasts, showing a good biocompatibility, so it might be an ideal surface modification method on magnesium alloys.

Bioactive Ca-P coating with self-sealing structure on pure magnesium.

Bioactive coatings containing Ca and P with self-sealing structures were fabricated on the surface of pure magnesium using micro-arc oxidation technique (MAO) in a specific calcium hydroxide based electrolyte system. Coatings were prepared at three applied voltages, i.e. 360, 410 and 450 V, and the morphology, chemical composition, corrosion resistance and the degradation properties in Hank's solution of the MAO-coated samples with three different applied voltages were investigated. It was found that all the three coatings showed similar surface morphologies that the majority of micro-pores were filled with compound particles. Both the porous structures and the compound particles were found to contain consistent chemical compositions which were mainly composed of O, Mg, F, Ca and P. Electrochemical tests showed a significant increase in corrosion resistance for the three coatings, meanwhile the coating obtained at 450 V exhibited the superior corrosion resistance owing to the largest coating thickness. The long term immersion tests in Hank's solution also revealed an effective reduction in corrosion rate for the MAO coated samples, and the pH values of the coated samples always maintained a lower level. Besides, all the three coatings were subjected to a mild and uniform degradation, while the coating obtained at 360 V showed a relatively obvious degradation characteristic and appreciable Ca and P contents on the surfaces of the three coatings were observed after immersion in Hank's solution. The results of the present study confirmed that the MAO coatings containing bioactive Ca and P elements with self-sealing structures could significantly enhance the corrosion resistance of magnesium substrate in Hanks' solution with great potential for medical application.

Molecular characterization and functional analysis by heterologous expression in E. coli under diverse abiotic stresses for OsLEA5, the atypical hydrophobic LEA protein from Oryza sativa L.

In this study, we report the molecular characterization and functional analysis of OsLEA5 gene, which belongs to the atypical late embryogenesis abundant (LEA) group 5C from Oryza sativa L. The cDNA of OsLEA5 contains a 456 bp ORF encoding a polypeptide of 151 amino acids with a calculated molecular mass of 16.5 kDa and a theoretical pI of 5.07. The OsLEA5 polypeptide is rich in Leu (10%), Ser (8.6%), and Asp (8.6%), while Cys, Trp, and Gln residue contents are very low, which are 2, 1.3, and 1.3%, respectively. Bioinformatic analysis revealed that group 5C LEA protein subfamily contains a Pfam:LEA_2 domain architecture and is highly hydrophobic, intrinsically ordered with largely ß-sheet and specific amino acid composition and distribution. Real-time PCR analysis showed that OsLEA5 was expressed in different tissue organs during different development stages of rice. The expression levels of OsLEA5 in the roots and panicles of full ripe stage were dramatically increased. The results of stress tolerance and cell viability assay demonstrated that recombinant E. coli cells producing OsLEA5 fusion protein exhibited improved resistance against diverse abiotic stresses: high salinity, osmotic, freezing, heat, and UV radiation. The OsLEA5 protein confers stabilization of the LDH under different abiotic stresses, such as heating, freeze-thawing, and drying in vitro. The combined results indicated that OsLEA5 protein was a hydrophobic atypical LEA and closely associated with resistance to multiple abiotic stresses. This research offered the valuable information for the development of crops with enhanced resistance to diverse stresses.